Hyperostosing meningiomas of the sphenoid wings. Results of surgical treatment in 32 cases

From 1987 to 1995 32 patients (24 females and 8 males, mean age 46 year) have been operated on at the Neurosurgical Dept. of the Istituto Nazionale Neurologico of Milan. 7 patients had been operated previously elsewhere. The orbit was invaded in every case and in 30 of them an intradural component of the tumor was present. The cavernous sinus was involved in 14 cases and 2 patients had previously their orbit exenterated due to marked proptosis. Of the remaining 30 patients 7 were already blind in the involved eye, 8 presented with marked visual impairment and proptosis was detected in every case. A campimetric defect was present in 6 patients. A deficit of the Vth cranial nerve was detected in 6 patients and an oculomotor deficit was present in 7 patients. A CT scan with bone algorythms and thin sections was obtained in every case; in some of them a pre and post-op 3D reconstruction was obtained. MRI was performed in 30 patients, with and without Gadolinium, to better demonstrate the dural infiltration and the intradural component of the tumor. Angiography was obtained in 2 patients only: in 1 a balloon test occlusion of the carotid artery was done while in the other patient the middle meningeal artery was embolized. A fronto-temporal craniotomy or craniectomy was done in every case, followed by extradural removal of the sphenoid wings, roof and lateral wall of the orbit, anterior clinoid process and opening of the optic canal. The tumor is then resected from the orbit and the dura of the middle cranial fossa. Removal of the intracavernous component has been attempted in 6 patients, but some tumor always remained inside the sinus. There was 1 surgical fatality and post-operative hemiparesis which did not clear during the follow-up, appeared in 1 case. Complete neuroradiological removal of the tumor was obtained in 10 cases; all the patients with cavernous sinus invasion had residual tumor inside the sinus. 4 patients had residual intraorbital tumor and in 6 a small hyperostotic residual was demonstrated. Up to now there has been no recurrence of radically resected tumors, while the residual intraorbital component has always regrown; conversely we did not find any growth of the residual intracavernous sinus component, or of residual hyperostotic lesion. Proptosis diminished or disappeared in every patient except 4. Oculomotor nerves deficits, when present pre-operatively, never improved in our series, and moreover improvement of pre-existing visual and campimetric deficits has been unusual. Conversely, in 3 patients only the visual function deteriorated because of the operation. Meticolous precocious aggressive surgery offers the best results in these rare tumors.